Fig. 2
From: Earth’s rotation variability triggers explosive eruptions in subduction zones
a Cumulate curve of ΔLODeff prior to major explosive eruptions (422 events with VEI ≥3) since 1850 and corresponding r E/W ratio, calculated for each of the four equal-sized classes (quartiles; red dots) of ΔLODeff. The most intense accelerations of Earth’s spin (i.e. negative ΔLODeff values below the 25th percentile) are followed by an increase of the number of eruptions along W (or SW)-directed subduction zones and by a decrease of eruptions along the E (or NE)-directed (i.e. r E/W ratio decreases by 28 % below the mean value). For the definition of “E” and “W” subduction classes, see the text. After significant Earth’s spin deceleration (i.e. ΔLODeff increases above the 75th percentile), r E/W ratio increases by 35 % above the mean. Cumulative probability density function (PDF) of year-to-year LOD changes (median values) obtained from 104 Monte Carlo simulations (b and c). The two synthetic PDF curves refer to the distribution of ΔLODeff changes (median values) for a sample of 256 events (i.e. corresponding to the number of eruptions that occurred on W-directed slabs) (b) and for a sample of 166 events (i.e. number of eruptions on E-directed slabs) (c) during the 1850 to 2009 time interval. Vertical dotted lines represent the mean standard deviation confidence levels. The comparison with the synthetic PDF distributions indicates that the observed LOD changes before eruptions on W- and E-directed slabs are significant at the >98 and >95 % confidence intervals, respectively